MICROPARA

• Microscope


  An instrument for viewing objects that are too small to be seen easily by the naked eye
• Historical Development of the Microscope

  1. Abbas Ibn Fimas - First vision aid was invented called a reading stone

  2. Salvino D' Armate - Credited with inventing the first wearable eye glasses

  3. Zaccharias and Hans Janssen - Experimented with multiple lenses place in a tube; forerunner of both microscope and telescope

  4. Galileo - Described the principles of lenses and light rays and improved both the microscope and telescope

  5. Robert Hooke (1665) - Looked into the cork and noticed some pores or cells in it

  6. Anton van Leeuwenhoek (1674) - Built a simple microscope with one lens and examined the blood, yeast, insects and many other tiny objects

  7. 18th century - Technical innovations improved microscopes

  8. Joseph Jackson Lister(1830) - Reduces spherical aberration or the chromatic effect

  9. Carl Zeiss (1850) - Began making refinements to the lenses

  10. Otto Schott (1880) - Conducted research on optical glass, greatly contributing to the improvement of the optical quality of the microscope

  11. Ernest Abbe (1872) - Wrote a mathematical formula called Abbe Sine Condition and added the condenser in the microscope

  12. Richard Zsigmondy (1903) - Developed the ultra-microscope

  13. Frits Zernike (1932) - Invented the phase-contrast microscope

  14. Ernst Ruska (1931) - Co-invented the Electron microscope

  15. Gerd Binnig and Heinrich Rohrer (1981) - Invented the scanning tunneling microscope
• Magnifying Parts


  • Eyepiece - Contains a magnifying lens that focuses the image from the objective into your eye
  • Low Power Objective (10x) - For large specimens or overview
  • High Power Objective (40x) - For detailed viewing or small specimens
  • Oil immersion Objective (100x) - For viewing bacteria and molds
• Mechanical Parts


  • Stage - Supports specimen in correct location to lens
  • Stage clip - Holds the slides in proper place
  • Draw tube - Connects the eyepiece to the objective lenses
  • Revolving nosepiece - Has holders for the different objective lenses. It allows the rotation of the lenses while viewing
  • Course Adjustment - For focusing under low magnification
  • Fine Adjustment - For focusing under high magnification or low
  • Arm - Supports the tube of the microscope and connects to the base
  • Base - Provides basal support for the microscope
  • Body tube - Light passes through this hollow tube; maintains correct distance between ocular lens and objective lenses
  • Pillar - Connects the base and the arm
  • Inclination joint - Permits tilting of the microscope
• Illuminating Parts


  • Light source (lamp) - Increases the amount of light shining through your specimen
  • Mirror - Concave, Plain, or Convex - Source of light
  • Condenser - Focuses the light on specimen
  • Diaphragm (iris or disc) - Regulates amount of light and contrast
• Optical Microscope


  • Uses visible light transmitted through, refracted around, or reflected from a specimen
  • Light waves are chaotic; an incandescent light source emits light waves traveling in different paths and of varying wavelengths
  • Some of the lenses in a microscope bend these light waves into parallel paths, magnify and focus the light at the ocular
• Magnification


  • The power to enlarge the image of the specimen when viewed through a microscope
  • Determined by how much the lenses bend the light waves
  • Expressed in numeric multiples of how much enlargement occurs with a lens
  • Total magnification is determined by multiplying the magnifications of the objective and ocular lenses
  • Higher magnification means the lens must be closer to the specimen (shorter focal length)
• Resolution


  • The property to show details clearly
  • Determined by the frequency of the light waves illuminating the specimen and the quality of the lens
  • Shorter wavelength = greater resolution
• Contrast


  • The darkness of the background relative to the specimen
  • Lighter specimens are easier to see on darker backgrounds
  • Staining the specimen may be necessary to obtain the contrast needed to view details
• Working Distance


  • The distance between the end of the objective and the tip of the specimen
  • As magnification increases, working distance decreases
• Par Focal


  The ability of the microscope to keep a specimen, which is in focus at one power, remains approximately in focus at all other powers
• Par Central


  The ability of the microscope to keep a specimen, which is in the center of the field at one power, remains approximately in the center of the field at all other powers
• Numerical Aperture


  • The measure of a microscope objective's ability to gather light and resolve fine specimen detail while working at a fixed object distance
  • The width of the cone of light that may enter the lens
  • A property of the lens, usually written on it, that indicates the light gathering power
• How to Use and Adjust a Compound Microscope

  Video link: https://www.youtube.com/watch?v=oQN30kduZWY&list=RDCMUCZlC75i7vizXvq0Dp3CKsuw&start_radio=1&rv=oQN30kduZWY&t=12
• Cleaning Your Microscope


  1. Dust and debris accumulate on microscopes that are left uncovered or are not regularly used

  2. Contaminants can be transferred from users and the environment

  3. Use the microscope cover and keep the work environment clean and at constant temperature

  4. Follow manufacturer's recommendations for cleaning products

  5. Use distilled water or 90%+ isopropyl alcohol to clean

  6. Avoid internal lens surfaces, use lens paper for immersion oil

  7. Do not use paper tissues or towels, use cotton cloth instead
• Types of Optical Microscopes

  • Light Microscopes
  • Simple Microscope
  • Compound Microscope
  • Dissection or Stereo Microscope
  • UV Microscope
  • Inverted Microscope
  • Metallurgic Microscope
  • Digital Microscope
• Light Microscopes


  • Based on the principle of light and lens
  • A light source illuminates the object while the lens magnifies it for viewing
• Simple Microscope


  • Uses a single lens for magnifying samples
  • Regarded as primitive with less relevance in serious scientific work
• Compound Microscope


  • Uses two different optical parts for magnifying objects
  • Most commonly used in laboratories
  • Can magnify objects up to 2000 times the original size
  • Used mainly for the study of cells, chromosomes and DNA
• Dissection or Stereo Microscope

  • Allows 3D viewing of objects
  • Contains lenses at different angles for a three dimensional view
  • Has top and bottom lighting for dissecting and viewing
• Other Optical Microscopes


  • UV Microscope
  • Inverted Microscope
  • Metallurgic Microscope
  • Digital Microscope
• Digital Microscope


  • Uses optical lens and CCD/CMOS sensors to magnify objects up to 1000 times
  • Has a 2 million pixel camera for high quality recording
  • Connected to a TV monitor for high resolution viewing
• Electron Microscope


  • Powered by a beam of electrons that strikes objects to magnify them
  • Used for studying cells and small particles of matter, as well as large objects
• Types of Electron Microscopes

  • Transmission Microscope
  • Scanning Electron Microscope
  • Reflection Electron Microscope
• Transmission Electron Microscope


  Used for studying cells and tiny slices of microorganisms after staining and placing on a wire grid
• Scanning Electron Microscope


  • Has lower magnifying power but can provide 3D viewing of objects
  • The image is captured in black and white after staining with gold and palladium
• Reflection Electron Microscope


  Uses electron beams but is different from transmission and scanning electron microscopes in that it is built to detect elastically scattered electrons
• Other Specialized Microscopes


  • X-ray Microscope
  • Scanning Acoustic Microscope
• 1. ray Microscope


  Uses X-ray beams to create images of an object
• Scanning Acoustic Microscope


  • Makes use of sound waves to detect images
  • Used for detecting cracks in materials and uncovering elasticity and stress in biological structures
• Viruses


  Acellular, non-living particles
• Viruses are not considered to be living organisms because they are incapable of carrying out all life processes
• Factors that distinguish viruses as non-living

  • They are not made of cells
  • They are obligate intracellular parasites
  • They can pass through filter
  • They can't reproduce on their own
  • They do not grow or undergo division
  • They do not transform energy
  • They lack machinery for protein synthesis - do not have the enzymes
  • They are so small that they can only be seen with an electron microscope
• Nucleic acid


  Can be either DNA or RNA, encodes the genetic information that is necessary to make copies of the virus
• Deoxyvirus


  Bacterial and animal viruses have DNA only
• Ribovirus


  Plant viruses have RNA only
• Capsid


  A protective protein coat that surrounds the nucleic acid which is made up of repeating proteinaceous structural units called capsomeres
• Functions of the Capsid

  • Protects enclosed nucleic acid from physical destruction and enzymatic hydrolysis by host cell nucleases
  • Gives shape
  • For attachment
  • With antigenic specificity which determines the type of cell, the virus can infect
• Envelope


  An outer membranous layer that surrounds some viruses made of lipid, glycoprotein and protein
• Envelope usually occurs as spikes for attachment to host cell receptor